Lithium-ion Batteries for New Japanese Submarines. Soryu Table.

Submarine Matters looks at Japanese submarines in detail with periodic updates (for example on August 26, 2016). The following is the latest update followed by the SORYU TABLE. The Japanese Navy (JMSDF)
is highly likely to be the first Navy to use Lithium-ion Batteries (LIBs) on
its diesel-electric submarines. At the same time these new submarines, known as
Soryu Mark 2s, will not use the existing Stirling AIP systems.

The first Soryu Mark 2 (with LIBs, no AIP) carries Soryu program number “27SS” (see table below). Construction of 27SS at the MHI
shipyard in Kobe began in 2015. 27SS might be launched this year (2017) (with
LIBs being inserted after launch?). With such a new battery technology for submarine use 27SS will undergo many more trials/tests and exercises than usual, It may be commissioned by 2020.

The arrangement of batteries, including LIBs, has many implications and
affects, influencing:

- a submarine’s overall arrangement of all the other large
internal items (fuel tanks, command center

location, diesel placement etc)

- balance/buoyancy of the submarine

- ease of removing old LIBs and placing in new ones

- electronic control of function and performance of the 100s of batteries used

- particularly avoiding runaway heat buildup in battery
groups

- emergency measures

- minimising the batteries' electromagnetic emissions out of the
sides and bottom of the submarine

10 comments:

Heavy LIBs (770kg) shown in the figure must be anchored to the pedestal. I assumed approach for anchoring as follows. First, a battery module comsisted of 8 single cells, where bottom two positions are empty, is placed on the pedestal. Next, the battery module is anchored to the pedestal by bolts using the bottom empty positions. After anchoring a battery module, 2 single cells are fixed in the bottom two positions. That is why the bottom two cells seems to be put in and out as shown in the figure.

As extra space for anchoring is required in this approach, adoption of the central aisle on the keel, LIBs-front facing the aisle, and 6-6 row LIBs-arrangement across the aisle is reasonable.

From Japanese Indutrial Standard (JIS) for LIBs installation in ships [1] and pictures of prototype LIBs of JMSDF, I estimated the instrallation process of LIBs, because any equipment needs proper installation. JIS requires anchoring of LIBs by bolts and nuts, but, I could not find position for bolting ouside of the battery module. It means that bolting is conducted inside and bottom of the battery module. Space for work is needed in bolting. If the bottom two positions are occupied by two single cells, we cannot use instruments for bolting.

[1] One of requirements for installation is ”battery sytems shall be anchored in the robust structural elements of ship by bolts and nuts.”

1. Are empty positions efficient?Yes2. is "empty" better than having all positions being used by cells?Yes3. Might thoses two positions being empty allow for better temperature control? orThere may be enough space inside of battery module, because widith of single cell is considerably narrow..4. Other necessary forms of battery control?Sorry, I do not know

As electrical current induces stray magnetic field, which provides distortion of geomagnetic field to be possiblily detected by MAD, minimization of stray magnetic field shoud be taken into account in arrangement of modern convensional submarine.

Minimization of stray magnetic field will be achieved by partial cancellation of magnetic field through alternative arrangement of two battery modules with opposite current loop. So, for the n-row by m-column array of battery modules, n and m are even numbers, and for the submarine with two battery sections, m is multiples of four.

Though close packed arrangement of battery modules [1] without the pedestal in terms of minimization of stray magnetic field and lowering of gravity center, I suppored arrangement with the pedestal because of installation and maintainance. But I can not find data or idea which supports my proposal, as arrangement of battery module is top secret or as my proposal is wrong.

I used to assume that LABs exchange is conducted by using both vertical and horizontal hydraulic jacks. This idea may be wrong [1]. Then, there is no the pedestal and battery modules for LABs are arranged in fully closed packing manner. LIBs may adopt nearly same arrangement. I am sorry.

Refernce [1] provides detail information on LABs, and we can understand that LIBs are perfectly different from LABs. The former needs fire extinguishing system including gas cylinder and piping, instead of ventilation system and water cooling system for the latter.

First, it takes quite long time to develop LIBs and great deal of effort tward establishment of their safety and reliability. I think in modern quality control system, theoretical approach assisted by computer simulation provides elucidation of failure mode and prediction of life time. But, these theoretical results still need validation through pratical use or experiment which takes time.

Second, battery system replacement from LABs to LIBs is never easy job. This replacement process includes elimination of ventilation system and water cooling sytem, total change of electrical system, installation of gas cylinder and piping for fire extinguishing, weight balancing, and so on. So, LIBs dictated optimum design is recommended rather than LABs-to-LIBs replacement in LABs submarine.

Submarine Matters

Director, Submarine Matters International. I analyse international trends, technical and political - mainly on submarines, sometimes on surface ships, aircraft, missiles and their nuclear warheads. This website started in 2007. I have a Masters Degree (International Relations (Strategic Studies)) High Distinction average. I'm happy to do research projects commissioned by consultancies, etc. The best way to navigate this site is to put a keyword in the search box top left corner.